Seed Inorganic Phosphorus Stability and Agronomic Performance of Two Low‐Phytate Soybean Lines Evaluated across Six Southeastern US Environments

Abstract

Nondigestible phytate salts that chelate nutritional minerals in the digestive tract of monogastric animals are an unwanted component of soymeal [Glycine max (L.) Merr.] and a documented source of nonpoint phosphorus (P) pollution in the waste stream detrimental to the environment. Lowering soybean phytate levels would ease environmental concerns and improve soymeal mineral bioavailability. In 2013, a field trial consisting of two University of Tennessee low‐phytate (LP) lines (56CX‐1273 and 56CX‐1283) and two high‐yielding check cultivars (‘5002T’ and ‘Osage’) were planted in four row plots in two replications at six Southeastern locations in a randomized complete block design to evaluate the LP lines for agronomic performance, seed quality traits and inorganic P (Pi) stability. Results revealed that there were no significant differences (P > 0.05) for mean seed yield or field emergence (germination) between the two LP lines and the two cultivars. Although the genotype × environmental index linear regression of seed Pi for the two LP lines revealed a slope that was significantly different (P < 0.001) from zero, and therefore not stable across the six environments, the mean Pi concentrations for LP lines 56CX‐1273 (2084.7 μg g−1) and 56CX‐1283 (1744.4 μg g−1) were still about an order of magnitude greater than the means of Osage (185.7 μg g−1) and 5002T (228.0 μg g−1). This study documents that a LP line can produce seed yields statistically equivalent to high‐yielding check cultivars with no germination issues.